Two-dimensional optical scanning mirror device, manufacturing method for same, two-dimensional optical scanner and image projector

ABSTRACT

A two-dimensional optical scanning mirror device, a manufacturing method for the same, a two-dimensional optical scanning device and an image projector. A two-dimensional optical scanning mirror device includes a substrate, a movable mirror portion supported on the substrate in such a manner that two-dimension optical scanning is possible, a hard magnetic thin film provided in the movable mirror portion and a magnetic field generator that includes at least an alternating magnetic field generator for driving the movable mirror portion, where the hard magnetic thin film has a magnetization direction in a direction of a film plane, and the ratio of the magnetic field generated by the magnetic field generator relative to the coercive force of the hard magnetic thin film is 0.2 or lower.

This application is a divisional of U.S. application Ser. No.16/193,084, filed on Nov. 16, 2018, which is a Continuation of aNational Stage of International Application No. PCT/JP2017/038740, filedon Oct. 26, 2017, which claims priority to Japanese priority applicationNo. 2016-212976 filed on Oct. 31, 2016, which are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to a two-dimensional optical scanningmirror device, a manufacturing method for the same, a two-dimensionaloptical scanner and an image projector, and in particular, to thestructure of a reflecting mirror device for scanning a light beam, and amanufacturing method for the same as well as a two-dimensional opticalscanner and an image projector using the same.

BACKGROUND ART

Various optical scanning mirror devices are known as conventionaldevices for scanning a light beam such as a laser beam in two directionsthat are orthogonal to each other. From among these, MEMS (Micro ElectroMechanical Systems) mirror devices are widely used because the devicescan be miniaturized.

MEMS mirror devices are known to include the electrostatic drive type,the piezo drive type and the electromagnetic drive type in accordancewith the drive system. From among these, electromagnetic drive type MEMSoptical scanning mirror devices use the force in a magnetic field.

A “movable coil system” where a coil is formed in a movable portion forscanning light so that a mirror can be rotated within a specified anglerange using Lorentz force in a static magnetic field applied from theoutside has been proposed for the electromagnetic drive type MEMSoptical scanning mirror device. (See Patent Literature 1 or PatentLiterature 2.) In addition, a “movable magnet system” where a magneticbody is formed in a movable portion for scanning light so that a mirrorcan be rotated within a specified angle range using repulsion andattraction in a modulated magnetic field applied from the outside hasbeen proposed (see Patent Literature 3 or Non-Patent Literature 1).

CITATION LIST Patent Literature

Patent Literature 1: Japanese Laid-open Patent Publication No.2008-242207

Patent Literature 2: Japanese Laid-open Patent Publication No.2016-012042

Patent Literature 3: Japanese Laid-open Patent Publication No.2010-049259

Patent Literature 4: Japanese Laid-open Patent Publication No.2013-195603

Patent Literature 5: U.S. Laid-open Patent Publication No. 2010/0073262

Non-Patent Literature

Non-Patent Literature 1: IEEE Photonics Technology Letters, Vol. 19, No.5, pp. 330-332, Mar. 1, 2007

SUMMARY OF INVENTION Problems to be Solved by the Invention

From among the above-described electromagnetic drive type MEMS mirrordevices, in the latter movable magnet system, it is necessary to form amagnetic body in a movable portion for scanning light, and thus, such aproblem arises that it is difficult to miniaturize the movable portionfor scanning light due to the formation of a magnetic body in additionto a mirror because magnetic bodies usually are of a large volume.Another problem arises where the structure of the movable portion iscomplex as compared to movable portions consisting of only a mirror.These problems are fatal for the formation of MEMS mirror devices,particularly compact ones.

An object of the present invention is to simplify and miniaturize thestructure of the movable mirror portion.

Means for Solving the Problems

According to one aspect, a two-dimensional optical scanning mirrordevice has a substrate, a movable mirror portion that has an opticalscanning rotation axis and is supported on the substrate in such amanner that two-dimensional optical scanning is possible, a hardmagnetic thin film provided in the movable mirror portion, and amagnetic field generator that includes at least an alternating magneticfield generator for driving the movable mirror portion are provided onthe substrate, where the magnetization direction of the hard magneticthin film is in the direction of the film plane, and the ratio of themagnetic field generated by the magnetic field generator to the coerciveforce of the hard magnetic thin film is 0.2 or less.

According to another aspect, a manufacturing method for atwo-dimensional optical scanning mirror device includes the step offorming a hard magnetic thin film on a substrate, the step ofmagnetizing the hard magnetic thin film, and the step of forming amovable mirror portion by processing the magnetized hard magnetic thinfilm.

According to still another aspect, a two-dimensional optical scannerincludes a two-dimensional optical scanning mirror device as describedabove and a light source formed on the substrate.

According to yet another aspect, an image projector includes atwo-dimensional optical scanner as described above, a two-dimensionaloptical scanning controller for two-dimensionally scanning light that isemitted from a light source as described above by applying atwo-dimensional optical scanning signal to the alternating magneticfield generator, and an image formation unit for projecting the emissionlight that has been scanned onto a projection plane.

Advantageous Effects of the Invention

As one advantageous effect, it becomes possible to simplify andminiaturize the structure of a movable mirror portion.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic perspective diagram illustrating an example of thetwo-dimensional optical scanning mirror device according to anembodiment of the present invention.

FIGS. 2A and 2B are diagrams illustrating an example of the structure ofthe reflection portion.

FIGS. 3A and 3B are diagrams illustrating another example of thestructure of the reflection portion.

FIGS. 4A and 4B are diagrams illustrating still another example of thestructure of the reflection portion.

FIGS. 5A and 5B are diagrams illustrating a method for magneticallyinclining the movable mirror portion.

FIG. 6 is a schematic perspective diagram illustrating an example of thetwo-dimensional optical scanner according to an embodiment of thepresent invention.

FIG. 7 is a schematic diagram illustrating the configuration of theimage projector according to an embodiment of the present invention.

FIG. 8 is a schematic perspective diagram illustrating thetwo-dimensional optical scanning mirror device according to Example 1 ofthe present invention.

FIGS. 9A and 9B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 1 of the present invention.

FIGS. 10A through 10C are diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 1 of the present invention during the manufacturing processup to a certain point before completion.

FIGS. 10D through 10F are diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 1 of the present invention during the manufacturing processafter the point in FIG. 10C and up to another point before completion.

FIGS. 10G through 10I are diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 1 of the present invention during the manufacturing processafter the point in FIG. 10F.

FIG. 11 illustrates a magnetic hysteresis curve for the Fe₅₆Pt₄₄ filmfabricated in Example 1.

FIGS. 12A and 12B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 2 of the present invention.

FIGS. 13A and 13B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 3 of the present invention.

FIGS. 14A and 14B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 4 of the present invention.

FIGS. 15A and 15B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 5 of the present invention.

FIGS. 16A and 16B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 6 of the present invention.

FIGS. 17A through 17C are diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 7 of the present invention during the manufacturing processup to a certain point before completion;

FIGS. 17D through 17F are diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 7 of the present invention during the manufacturing processafter the point in FIG. 17C and up to another point before completion.

FIGS. 17G through 17I are diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 7 of the present invention during the manufacturing processafter the point in FIG. 17F.

FIGS. 18A and 18B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 8 of the present invention.

FIGS. 19A and 19B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 9 of the present invention.

FIG. 20 is a schematic perspective diagram illustrating thetwo-dimensional optical scanning device according to Example 10 of thepresent invention.

FIG. 21 is a schematic perspective diagram illustrating thetwo-dimensional optical scanning device according to Example 11 of thepresent invention.

FIG. 22 is a schematic perspective diagram illustrating thetwo-dimensional optical scanning device according to Example 12 of thepresent invention.

DESCRIPTION OF EMBODIMENTS

In reference to FIGS. 1 through 7, an example of the two-dimensionaloptical scanning mirror device according to an embodiment of the presentinvention is described as follows. The present invention can be providedsince the present inventor has reached the conclusion as a result ofdiligent research that it is possible to simplify and miniaturize thestructure of a movable mirror portion by using a magnetic thin film forthe magnetic body instead of a conventional bulk magnetic body. The useof a magnetic thin film makes it possible to provide a lighter movablemirror portion so that the magnetic field for driving the system can bemade smaller. In addition, the above-described problems are solved byusing a hard magnetic thin film of which the coercive force is apredetermined value or higher, particularly a hard magnetic thin film ofwhich the coercive force is such that the ratio of the magnetic fieldgenerated by the magnetic field generator 30 that at least includes analternating magnetic field generator to the coercive force is 0.2 orless, that is to say, the magnitude of the coercive force is 5(=1/0.2)times greater or more of the magnetic field generated by the magneticfield generator 30 in order to compensate the decrease in the coerciveforce in the case where the magnetic thin film is used.

FIG. 1 is a schematic perspective diagram illustrating thetwo-dimensional optical scanning mirror device according to anembodiment of the present invention, which is provided with a movablemirror portion 10 and a magnetic field generator 30 that includes atleast an alternating magnetic field generator for driving the movablemirror portion 10. The movable mirror portion 10 has a reflectionportion 20, a rotational outer frame 12 for supporting the reflectionportion 20 with a pair of first hinges 11 that provide a first opticalscanning rotation axis, and a non-rotational outer frame 14 forsupporting the rotational outer frame 12 with a pair of second hinges 13that provides a second optical scanning rotation axis in the directionthat is orthogonal to the first hinges 11. It is necessary to determinethe high-speed rotation of the first hinges 11 and the second hinges 13to be the rotational frequency that is inherent to the reflectionportion 20. This inherent rotational frequency is determined by the formand mass of the reflection portion 20, the spring constant of therotational portion and the like. The thickness of the first hinges 11and the second hinges 13 is approximately 2 μm to 50 μm, and typicallythe thickness is 10 μm.

FIGS. 2A and 2B are diagrams illustrating an example of the structure ofthe reflection portion. FIG. 2A is an upper diagram, and FIG. 2B is across-sectional diagram along the single-dotted chain line connecting Aand A′ in FIG. 2A. The reflection portion 20 has a substrate 21 and ahard magnetic thin film 22 provided on the substrate 21. The hardmagnetic thin film 22 has a large coercive force of which thedemagnetization curve protrudes greatly, and thus can be a permanentmagnet. Here, the hard magnetic thin film 22 is defined so as to have acoercive force of 10 kA/m or greater. According to the presentinvention, however, the hard magnetic thin film 22 may have a coerciveforce that is five times greater or more than that of the magnetic fieldgenerated by the magnetic field generator 30, and a hard magnetic thinfilm having a coercive force of 100 kA/m or greater is preferable.Hereinafter, a preferable example of the present invention is describedusing a hard magnetic thin film that has a coercive force of 100 kA/m orgreater.

When the movable mirror portion 10 is operated repeatedly, the magneticfield force working in the direction of the high-speed rotationfrequently interrupts the external magnetic field for driving thesystem, and therefore diminishes gradually. Meanwhile, the magneticfield force that is applied in the direction of the low speed rotationdoes not diminish much. Therefore, the direction of the magnetic fieldgradually becomes smaller than 45° relative to the direction of thehigh-speed rotation, and thus, the characteristics of the mirrordeteriorate. In the case where the coercive force is 100 kA/m orgreater, however, the deterioration of the mirror characteristics can besuppressed under a conventional state of use. Accordingly, the coerciveforce of 100 kA/m or greater is preferable in the case of atwo-dimensional operation. Here, the difference between the coerciveforce that is required for two-dimensional scanning and the alternatingmagnetic field is sufficiently great, and thus, the mirrorcharacteristics barely deteriorate even when the movable mirror portion10 is operated repeatedly in the case where the ratio of the magneticfield generated by the magnetic field generator 30 that includes atleast an alternating magnetic field generator to the coercive force is0.2 or less. In the experiments, only an alternating magnetic fieldgenerator was used as the magnetic field generator 30, and the magneticfield generated by a solenoid coil, which was used as the alternatingmagnetic field generator, was 2 kA/m to 20 kA/m (which corresponds to 25gauss to 250 gauss), and thus, the ratio of the magnetic field generatedby the alternating magnetic field generator to the coercive forcerequired for two-dimensional scanning was 0.2 or less in the case whereonly an alternating current for driving the mirror was made to flow.

The closer to 1 the squareness ratio is, the better the characteristicsas a permanent magnet are. As described below, according to the datameasured in the experiments, the squareness ratio (=residual magneticflux density Br/maximum magnetic flux density Bm)≈0.82, and therefore,it is desirable for the squareness ratio to be 0.7 or greater whenestimated from thus-calculated value.

Hard magnetic thin films such as the hard magnetic thin film 22generally have a high light reflectance, and therefore, the hardmagnetic thin film 22 can be used as a reflecting mirror, which makes itunnecessary to install an extra structure other than the hard magneticthin film 22 in the movable mirror portion 10. Thus, the structure ofthe movable portion in the movable mirror portion 10 is simplified,which makes miniaturization possible. In addition, it is not necessaryfor the hard magnetic thin film 22 to be provided only on the reflectionportion 20 in FIG. 1, but the hard magnetic thin film 22 may beadditionally formed on the rotational outer frame 12 and thenon-rotational outer frame 14. When the hard magnetic thin film 22 isformed on the rotational outer frame 12, the rotation around the lowspeed scanning axis becomes easier because the total force in themagnetic field becomes greater.

It is necessary for the hard magnetic thin film 22 to be magnetized inthe direction of the film plane, and in particular, it is desirable forthe direction of the magnetization of the hard magnetic thin film to beat an angle within a range of 45°+/−30° relative to the first hinges 11that provide the first optical scanning rotation axis of the movablemirror portion 10. When the direction is within this angle range, twoaxial rotation scanning becomes possible. Here, the shape of thereflection portion 20 is circular; however, it may be elliptical,square, rectangular or other polygonal shapes.

FIGS. 3A and 3B are diagrams illustrating another example of thestructure of the reflection portion. FIG. 3A is an upper diagram, andFIG. 3B is a cross-sectional diagram along the single-dotted chain lineconnecting A and A′ in FIG. 3A. The reflection portion 20 has asubstrate 21, a hard magnetic thin film 22 provided on the substrate 21,and a reflective film 23 that becomes a reflecting mirror provided onthe hard magnetic thin film 22, and is useful in the case where a higherlight reflectance is required. In this case as well, the structure ofthe movable mirror portion 10 is not complex only by being additionallyprovided with a reflective film 23, and thus, miniaturization ispossible.

FIGS. 4A and 4B are diagrams illustrating still another example of thestructure of the reflection portion. FIG. 4A is an upper diagram, andFIG. 4B is a cross-sectional diagram along the single-dotted chain lineconnecting A and A′ in FIG. 4A. The reflection portion 20 has asubstrate 21, a hard magnetic thin film 22 provided on one surface ofthe substrate 21, and a reflective film 23 provided on the other surfaceof the substrate 21. In this case as well, the reflection portion 20 isuseful in the case where a higher light reflectance is required, and thestructure of the movable mirror portion 10 is not complex only by beingprovided with a reflective film 23, and thus, miniaturization ispossible.

Though solenoid coils are typical examples of alternating magnetic fieldgenerators, an iron core made of soft iron with a coil being wound maybe used. Though it is desirable for the solenoid coils to be compact andable to generate a high magnetic field, the size thereof does not haveany limitations. When the present embodiment was implemented, forexample, a solenoid coil having an outer diameter of 5 mm and a heightof 3 mm, where the number of turns of the wire was 800, and a solenoidcoil having an outer diameter of 2.46 mm, an inner diameter of 1.21 mmand a height of 1.99 mm, where the number of turns of the wire was 600,were fabricated. Here, the alternating magnetic field generator is notlimited to solenoid coils, and any device that can generate a magneticfield that is sufficient for rotating the movable mirror portion 10 maybe used, and as an example, plane spiral coils formed in a spiral on aplane may be used.

As for the entire configuration of the movable mirror portion 10, therotational outer frame 12 and the non-rotational outer frame 14 may beformed of metal glass so that they can also function as a reflectingmirror or may be formed of a non-magnetic dielectric film such as a SiO₂film. In this case, the substrate 21 runs at least beneath thenon-rotational outer frame 14. Though a single crystal silicon substrateis a typical example of the substrate 21, a glass substrate or a crystalsubstrate may be used.

It is desirable for the hard magnetic thin film 22 to be a preciousmetal based magnetic film, particularly one made of any of a magneticmaterial having main components of Fe and Pt, a magnetic material havingmain components of Co and Pt, or a magnetic material having maincomponents of Fe and Pd. Though the thickness of the hard magnetic thinfilm 22 does not have any limitations, the thicker ones can make thetotal amount of the generated magnetic flux greater, and thus can makethe current flowing through the alternating magnetic field generatorsmaller. The thickness of the hard magnetic thin film 22 is in a rangefrom 10 nm to the thickness that is approximately the same as that ofthe substrate 21. In this case, the hard magnetic thin film 22 may havea two-layer structure with a non-magnetic insulating film such as a SiO₂film in between or may have a multiple-layer structure such as a threelayer structure, where the film thickness of each layer may be the sameor different and the composition of each layer may be the same ordifferent. The method for forming the film is not particularly limitedas long as a target film can be gained, and a vapor deposition method, asputtering method, a plating method and an application method can becited as examples.

The reflective film 23 may be made of any kind of material that reflectslight, and metal glass such as ZrCuAlNi, Fe-based metal glass, an Alfilm, an Au film or a dielectric multilayer film may be used. Inaddition, a protective film such as a SiO₂ film may be formed on theupper surface of the reflective film 23, between the reflective film 23and the hard magnetic thin film 22, between the hard magnetic thin film22 and the substrate 21, or on the bottom surface of the substrate 21.

In the case where the movable mirror portion 10 is integrated on thesame substrate as the light source for generating a light beam that isincident into the reflecting mirror, it is desirable for the reflectivesurface of the movable mirror portion 10 to be inclined relative to themain surface of the substrate 21, that is to say, relative to theincident light beam, at an angle within a range of 45°+/−30°. The methodfor inclining the movable mirror portion 10 in this manner includes amethod for inclining the reflection portion 20 and the rotational outerframe 12 relative to the light beam by a predetermined angle, forexample, 45°, with a mechanical external force and irradiating thesecond hinges 13 with a focused laser beam so as to locally heat thesecond hinges 13 in order to hold the state of the reflection portion 20and the rotational outer frame 12 inclined by 45°.

Another method may be to magnetically incline the movable mirror portion10. FIGS. 5A and 5B are diagrams illustrating a method for magneticallyinclining the movable mirror portion 10. FIG. 5A is a diagramillustrating a case where the movable mirror portion is inclined througha direct current bias. When a direct bias current is made to flowconstantly through the alternating magnetic field generator 31, themovable mirror portion can be inclined by 45° relative to the light beamthrough the interaction between the N pole of the magnetized reflectionportion 20 and the N pole of the alternating magnetic field generator 31that is generated by the direct bias current. As a result, analternating current signal can be made to flow in addition to thisdirect current so that the reflection portion 20 can be rotated with theposition where the reflection portion 20 is inclined by 45° at thecenter. In this case, the coercive force of the hard magnetic thin film22 is set to be five times greater or more of the magnetic field thatresults from the synthesis of the magnetic field generated by the directbias current and the magnetic field generated by the alternatingcurrent.

FIG. 5B is a diagram illustrating a case where the movable mirrorportion is inclined by using a permanent magnet. The movable mirrorportion 10 can be inclined by arranging a permanent magnet 32 beneaththe movable mirror portion 10. In this case, the coercive force of thehard magnetic thin film 22 is set to be five times greater or more ofthe magnetic field that has been synthesized from the magnetic fieldgenerated by the permanent magnet 32 and the magnetic field generated bythe alternating magnetic field generator 31. Here, it is also possibleto reflect the light beam toward the plate side of the substrate 21 byinclining the movable mirror portion by 45° in the opposite direction byadopting the same structure of the movable mirror portion as illustratedin FIGS. 4A and 4B, which can also be applied to the case in FIG. 5A. Inthis case, the hard magnetic thin film 22 is also used as the reflectivefilm, and the reflective film 23 made of a metal glass film or the likemay be used as a member for forming the hinges.

In addition, the center axis of the alternating magnetic field generator31 can be shifted from the center portion of the reflection portion 20by a predetermined distance d along the direction of the optical axis ofthe light beam in order to make it possible to lower the intensity ofthe direct current by 50% as compared to the case where the center axisof the alternating magnetic field generator 31 and the center portion ofthe reflection portion 20 match. For example, it is possible to lowerthe intensity of the direct current by 50% by shifting the center axisof the alternating magnetic field generator 31 and the center portion ofthe reflection portion 20 by d=1 mm as compared to the case where thetwo match.

In order to fabricate a two-dimensional optical scanning mirror deviceas described above, a hard magnetic thin film 22 may be formed on asubstrate 21, and after that, the hard magnetic thin film 22 may bemagnetized in a magnetic field, and the magnetized hard magnetic thinfilm 22 may be processed to form a movable mirror portion 10. In thiscase, it is desirable for the hard magnetic thin film 22 to bemagnetized after the formation of the movable mirror portion 20 in sucha manner that the magnetization is achieved in such a direction at anangle within a range of 45°+/−30° relative to the rotation axis of theoptical scanning of the movable mirror portion 20.

Here, the hard magnetic thin film in the same state as being depositedhas a small coercive force, and therefore, it is desirable to anneal thehard magnetic thin film before the magnetizing process. The temperaturefor annealing may be optimized within a range between 200° C. and 1100°C. In addition, it is desirable for the magnetizing process to becarried out before the formation of the mirror structure. The rotationalouter frame 12 and the reflection portion 20 are supported only by thesecond hinges 13 and the first hinges 11 respectively, and therefore, amechanical stress generated through the application of a large magneticfield that is required for the magnetization would break the mirrorstructure.

Here, an orientation control film may be provided beneath the hardmagnetic thin film as a base layer in order to easily control thedirection of the magnetization of the hard magnetic thin film 22.Alternatively, a texturing process for creating trenches or making thesurface uneven on the SiO₂ film or the like that becomes the base may becarried out instead of providing the orientation control film.

A light source may be provided on the substrate 21 in theabove-described two-dimensional optical scanning mirror device in orderto form a two-dimensional optical scanner. Alternatively, atwo-dimensional optical scanning mirror device as described above may bemounted on a mounting substrate, and at the same time, a light sourcemay be mounted in a location where the two-dimensional optical scanningmirror device is to be irradiated with a laser beam. In this case, it isdesirable for the light source to have a red laser, a green laser, ablue laser and an optical multiplexer for multiplexing light outputtedfrom the red laser, the green laser and the blue laser. Alternatively,the light source may additionally have a yellow laser in order tovividly reproduce the color white. Furthermore, an infrared laser may besolely used or may be added to a multicolor visible light laser asdescribed above.

FIG. 6 is a schematic perspective diagram illustrating an example of thetwo-dimensional optical scanner according to an embodiment of thepresent invention. An optical multiplexer 41 may be provided on asubstrate 21 where a movable mirror portion 10 has been formed, and ared laser 42, a green laser 43 and a blue laser 44 may be coupled tothis optical multiplexer 41. Since the movable mirror portion 10 hasbeen miniaturized, the total size after integration can be made smallerin the case where the light source for generating a light beam isintegrated. Particularly, in the case of a light source where a lightbeam is emitted from a semiconductor laser or an optical multiplexer,such a semiconductor laser or optical multiplexer may be formed on a Sisubstrate or a metal plate substrate, and therefore, the formation of alight source and a two-dimensional optical scanning mirror device onthis type of substrate has such an effect that the total size afterintegration can be made smaller.

In order to form an image projector, a two-dimensional optical scanneras described above, a two-dimensional scanning controller fortwo-dimensionally scanning light that has been emitted from the lightsource by applying a two-dimensional optical scanning signal to themagnetic field generator 30 and an image forming portion for projectingthe emission light that has been scanned onto a projection surface maybe combined. Here, a typical example of the image projector is aspectacle-type retina scanning display (see Patent Literature 4).

FIG. 7 is a schematic diagram illustrating the configuration of theimage projector according to an embodiment of the present invention,where a typical example of the image projector is a spectacle-typeretina scanning display (see Patent Literature 4). The image projectoraccording to the embodiment of the present invention is to be worn onthe head of a user by using a spectacle-type accessory or the like (seePatent Literature 5).

A control unit 50 has a controller 51, an operating unit 52, an externalinterface (I/F) 53, an R laser driver 54, a G laser driver 55, a B laserdriver 56 and a two-dimensional scanning driver 57. The controller 51 isformed of a microcomputer that includes a CPU, a ROM, a RAM and thelike. The controller 51 generates an R signal, a G signal, a B signal, ahorizontal signal and a vertical signal for forming an image on thebasis of the image data that is supplied from an external apparatus suchas a PC via the external I/F 53. The controller 51 transmits the Rsignal to the R laser driver 54, the G signal to the G laser driver 55and the B signal to the B laser driver 56, respectively. In addition,the controller 51 transmits the horizontal signal and the verticalsignal to the two-dimensional scanning driver 57 and controls thecurrent to be applied to the magnetic field generator 30, and thuscontrols the operation of the movable mirror portion 10.

The R laser driver 54 drives the red laser 42 so that red laser light,of which the light amount is in accordance with the R signal from thecontroller 51, is generated. The G laser driver 55 drives the greenlaser 43 so that green laser light, of which the light amount is inaccordance with the G signal from the controller 51, is generated. The Blaser driver 56 drives the blue laser 44 so that blue laser light, ofwhich the light amount is in accordance with the B signal from thecontroller 51, is generated. It becomes possible to generate a laserbeam having a desired color by adjusting the intensity ratio of thelaser beams of the respective colors.

The laser beams respectively generated by the red laser 42, the greenlaser 43 and the blue laser 44 are multiplexed by the opticalmultiplexer 41, and after that two-dimensionally scanned by the movablemirror portion 10. The scanned multiplexed laser beam is reflected froma concave reflecting mirror 58 and passes through the pupil 59 so as toform an image on a retina 60.

In the embodiment of the present invention, a hard magnetic thin film 22is used in the movable mirror portion 20, and in particular, the hardmagnetic thin film 22 has a coercive force of 100 kA/m or greater, whichis desirable for two-dimensional scanning in such a manner that theratio of the magnetic field generated by the magnetic field generator 30to the coercive force becomes 0.2 or less, and therefore, a sufficientrotational force in the magnetic field can be secured only by using athin film without deteriorating the mirror characteristics, and thus,the movable mirror portion 20 can be miniaturized without making thestructure thereof complex. Unlike the movable magnet systems disclosedin Patent Literature 3 and Non-Patent Literature 1, it is not necessaryto embed a magnet in the periphery of the mirror, and thus, thestructure of the movable mirror portion can be simplified, which makesit possible to miniaturize the movable mirror portion.

Example 1

Next, the two-dimensional optical scanning mirror device according toExample 1 of the present invention is described in reference to FIGS. 8through 13. FIG. 8 is a schematic perspective diagram illustrating thetwo-dimensional optical scanning mirror device according to Example 1 ofthe present invention, which is provided with a movable mirror portion70 and a solenoid coil 90 for driving the movable mirror portion 70. Themovable mirror portion 70 has a reflection portion 80, a rotationalouter frame 82 for supporting the reflection portion 80 with a pair ofhinges 81, and a non-rotational outer frame 84 for supporting therotational outer frame 82 with a pair of hinges 83 that is provided inthe direction that is orthogonal to the hinges 81.

In this case, the hinges 81 provide a rotation axis for high speedscanning, and the hinges 83 provide a rotational axis for low speedscanning. The hard magnetic thin film made of an Fe—Pt thin filmprovided on the reflection portion 80 is magnetized in the directionthat is at 45° relative to the rotational axis for high speed scanningand the rotational axis for low speed scanning that are orthogonal toeach other. Thus, the magnetization direction is inclined by 45°relative to the two scanning axes, and thereby, two axial scanningbecomes possible by using a single solenoid coil 90. In this case,concerning the lines of magnetic force due to the magnetization of themovable mirror portion 70 that is inclined by 45° relative to therespective scanning axes, the components of the lines that areorthogonal to the respective scanning axes cause repulsion andattraction from and to the magnetic field of the solenoid coil 90, andthus cause reciprocal vibrations within a certain angle around therespective scanning axes.

The point where two axial scanning is carried out using only themagnetic force as described above characterizes the two-dimensionaloptical scanning mirror device according to Example 1 of the presentinvention. As illustrated in FIG. 8, the alternating current that ismade to flow through the solenoid coil 90 is obtained by overlapping alow speed scanning axis signal having a low frequency and a high speedscanning axis signal having a high frequency.

Concerning the high speed scanning, the scanning frequency thereof canbe adjusted so as to become approximate to the inherent rotationalfrequency (determined by the shape and mass of the mirror portion, thespring constant of the rotation axis and the like) around the hinges 81that provide a rotation axis of the movable mirror portion 70 so thatthe mirror can be rotated efficiently. Concerning the low speedscanning, it is not necessary to make the scanning frequency approximateto the inherent frequency of the rotation around the hinges 83 thatprovide the rotation axis for low speed scanning in order to make thelow speed scanning possible. Here, the scanning frequency that isapproximate to the inherent frequency of the rotation around therotation axis for low speed scanning can of course be used.

Though the reflection portion 80 is supported by the hinges 81 thatprovide a rotation axis for high speed scanning and the rotational outerframe 82 is supported by the hinges 83 that provide a rotation axis forlow speed scanning in this structure, conversely, the projection portion80 may be supported by the hinges 81 that provide a rotation axis forlow speed scanning and the rotational outer frame 82 by the hinges 83that provide a rotation axis for high speed scanning in the structure.

FIGS. 9A and 9B are schematic diagrams illustrating the movable mirrorportion of the two-dimensional optical scanning mirror device accordingto Example 1 of the present invention. FIG. 9A is an upper diagram, andFIG. 9B is a cross-sectional diagram along the single-dotted chain lineconnecting A and A″ in FIG. 9A. Though the size of the reflectionportion 80 and the entire size of the movable mirror portion 70 can bearbitrary, the size of the reflection portion 80 is 500 μm×300 μm, andthe size of the movable mirror portion 70 is 2.7 mm×2.5 mm. A Sisubstrate 71 is used to provide an Fe₅₆Pt₄₄ thin film 74 with a SiO₂film 72 in between, and the reflection portion 80, the hinges 81, therotational outer frame 82, the hinges 83 and the non-rotational outerframe 84 are formed of a metal glass film 75. Here, a part of the Silayer remains on the opposite surface of the SiO₂ film that makescontact with the Fe₅₆Pt₄₄ thin film 74 as a mirror base substrate 76 formaintaining the mechanical strength.

Next, the manufacturing process for the movable mirror portion of thetwo-dimensional optical scanning mirror device according to Example 1 ofthe present invention is described in reference to FIGS. 10A through10I. First, as illustrated in FIG. 10A, a silicon substrate 71 having athickness of 500 μm and of which the main surface is (100) plane isheated at 1,000° C. for one hour in the air so as to form SiO₂ films 72and 73 having a thickness of 10 nm to 150 nm. Here, the film thicknessof the SiO₂ film 72 is 100 nm.

Next, as illustrated in FIG. 10B, an Fe₅₆Pt₄₄ thin film 74 having athickness of 142 nm is deposited in accordance with an electron beamheating vapor deposition method. Then, the Fe₅₆Pt₄₄ thin film 74 isannealed through irradiation with infrared rays in a vacuum so as to beconverted to an alloy. Here, the temperature for heating is 650° C. andthe time for heating is 15 minutes. Next, the Fe₅₆Pt₄₄ thin film 74 ismagnetized by applying a magnetic field in the <011> direction of the Sisubstrate 71. Here, the intensity of the magnetic field formagnetization is 5 tesla and the time for magnetization is threeminutes.

Next, as illustrated in FIG. 10C, the Fe₅₆Pt₄₄ thin film 74 is processedin accordance with an ion milling method to a shape that corresponds tothe rotational outer frame 82 and the reflection portion 80 illustratedin FIG. 8. At this time, the directions of the hinges 81 and 83, that isto say, the optical scanning rotational axes of the mirror portion, aremade to be the same as the <010> direction of the Si substrate 71, andthereby, the direction of the magnetization is at 45 degrees relative tothe hinges 81 and 83. Then, as illustrated in FIG. 10D, a buffered HFsolution is used to remove the SiO₂ film 73 through etching so that theSiO₂ film 73 remains only in the outer peripheral portion of the Sisubstrate 71.

Next, as illustrated in FIG. 10E, a metal glass film 75 having such ashape as to correspond to the reflection portion 80, the hinges 81, therotational outer frame 82, the hinges 83 and the non-rotational outerframe 84 is formed in accordance with a lift-off method. The metal glassfilm 75 is formed as a film of Zr₇₅Cu₃₀Al₁₀Ni₅ having a thickness of 10μm in accordance with a sputtering method in an atmosphere of which thepressure has been reduced to 0.4 Pa. Here, the thickness of the metalglass film 75 depends on the inherent rotational frequency that isdetermined by the shape and mass of the reflection portion 20, thespring constant of the rotational portion and the like and isapproximately 2 μm to 50 μm, and is 10 μm in this example.

Next, as illustrated in FIG. 10F, the Si substrate 71 is etched on thebottom side so as to correspond to the pattern of the Fe₅₆Pt₄₄ thin film74. Then, as illustrated in FIG. 10G, the SiO₂ film 73 is used as a maskto dry etch the Si substrate 71 on the bottom side so that the SiO₂ film72 is partially exposed. At this time, a Si layer having a thickness ofapproximately 100 nm remains on the bottom side of the Fe₅₆Pt₄₄ thinfilm 74 as the mirror base substrate 76.

Next, as illustrated in FIG. 10H, a buffered HF solution is used tocompletely etch away the exposed portion of the SiO₂ film so that onlythe metal glass film 75 remains to provide the hinges 81 and 83. Then,as illustrated in FIG. 10I, the Si substrate 71 is diced so as to cutout a two-dimensional optical scanning mirror device, and thus, thebasic structure of the movable mirror portion 70 of the two-dimensionalscanning mirror device according to Example 1 of the present inventionis complete.

FIG. 11 illustrates a magnetic hysteresis curve for the Fe₅₆Pt₄₄ filmfabricated in Example 1. As illustrated in FIG. 11, the in-planedirection coercive force is 800 kA/m (approximately 10 kOe), and theresidual magnetization is approximately 0.8 tesla, and thus, asufficient coercive force is gained by using only a thin film. Inaddition, the squareness ratio (=residual magnetic flux densityBr/maximum magnetic flux density Bm)≈0.82.

As illustrated in FIG. 8, a two-dimensional optical scanning mirrordevice is provided by installing a solenoid coil 90 beneath the movablemirror portion 70. As for the size of the solenoid coil 90, the outerdiameter is 5 mm, the height is 3 mm and the number of turns of the wireis 800. The solenoid coil 90 makes direct connection on the Si substrate71 in the outer periphery of the movable mirror portion 70 with anadhesive in between and is fixed with the adhesive in such a state thatthe center portion of the solenoid coil 90 becomes the same as thecenter of the reflection portion.

This two-dimensional optical scanning mirror device was actuallyirradiated with a laser beam so that the reflected beam was projectedonto the screen, and thus, the deflection angle of the light beam wasevaluated. As a result, the deflection angle of the beam at 30° in thelongitudinal direction and at 5° in the lateral direction was obtainedwith an operational voltage of 2 V.

How the characteristics were affected by the external environment andthe repetitive use of the mirror was checked. The selected factors ofthe concrete external environment were the temperature of the outsideair and the external magnetic field, and changes in the characteristicsin response to the respective factors were found. As a result, nochanges were found in the characteristics even when the externaltemperature rose. In addition, no changes in the characteristics wereperceived even after a bar magnet for science education (the magnitudeof the magnetic field was approximately 50 kA/m) was made to approachthe optical mirror device as an external magnetic field. Meanwhile,changes in the operational characteristics after an optical scanningmirror device had continuously been in operation for one month werechecked in order to check how the repetitive use affected the mirror. Asa result, the deflection angle of the beam at 30° in the longitudinaldirection and 5° in the lateral direction was gained with an operationalvoltage of 2 V, and thus, the operational characteristics were notperceived as having deteriorated even after the continuous operation forone month before the deflection angle of the light beam was evaluated.

For the sake of comparison, the characteristics of a two-dimensionaloptical scanning mirror device that had been fabricated withoutannealing treatment after the formation of an Fe₅₆Pt₄₄ thin film in thesame manner as in Example 1 were evaluated. In this case, the coerciveforce was 10 kA/m, and the characteristics of the optical scanningmirror device immediately after fabrication were the same as in the casewhere annealing treatment was carried out to make the coercive force 800kA/m. However, the deflection angle of the beam at 15° in thelongitudinal direction and at 1° in the lateral direction was gainedwith an applied voltage of 2 V when the characteristics were measuredafter a bar magnet for science education (the magnitude of the magneticfield was approximately 50 kA/m) was made to approach thetwo-dimensional optical scanning mirror device as an external magneticfield. In this case, the characteristics of the optical scanning mirrordevice were worse when affected by an external magnetic field as afactor of the external environment as compared to that where themagnetic thin film had been annealed. In addition, the operationalcharacteristics were perceived to have deteriorated after thetwo-dimensional optical scanning mirror device had continuously been inoperation for one month.

For the sake of further comparison, the characteristics of atwo-dimensional optical scanning mirror device that had been fabricatedby carrying out annealing treatment after the formation of an Fe₅₆Pt₄₄thin film that was the same as in Example 1 and then irradiating thefilm with ²⁰Ne⁺ ions of 180 keV at room temperature were evaluated. Inthis case, the coercive force was 100 kA/m. The deflection angle of thebeam at 30° in the longitudinal direction and at 5° in the lateraldirection was gained with an applied voltage of 2 V, and thus, the samecharacteristics were gained as an optical scanning mirror device wherethe magnetic thin film had been annealed. In addition, the deflectionangle of the beam at 30° in the longitudinal direction and at 5° in thelateral direction was gained with an applied voltage of 2 V when thecharacteristics were measured after a bar magnet for science education(the magnitude of the magnetic field was approximately 50 kA/m) was madeto approach the optical mirror device as an external magnetic field. Inthis case as well, the same characteristics were gained as an opticalmirror scanning device where the magnetic thin film had been annealed.The operational characteristics of the optical scanning mirror devicewere not perceived to have deteriorated after continuous operation forone month.

It was found from these results that the coercive force of a magneticthin film is not affected by a change in the general externalenvironment such as the temperature and an external magnetic field orthe repetitive use of the mirror as long as it is 100 kA/m or greater,and thus, it was clarified that the coercive force was an importantparameter for the characteristics of an electromagnetic drive typeoptical scanning mirror when practically used. It could also beclarified that a coercive force of 100 kA/m or greater is actuallyrequired in the case where the two-dimensional optical scanning mirrordevice is miniaturized as illustrated in Example 1.

A hard magnetic film is used for the magnetic body in Example 1, andtherefore, a sufficient coercive force and a rotational force in amagnetic field can be secured even with a thin film. As a result, thestructure of the movable mirror portion can be simplified andminiaturized without the mirror characteristics being deteriorated, andthus, it becomes possible to miniaturize the entire size of thetwo-dimensional optical scanning mirror device.

Example 2

Next, the two-dimensional optical scanning mirror device according toExample 2 of the present invention is described in reference to FIGS.12A and 12B and is the same as that in Example 1, except that a Co₈₀Pt₂₀thin film is used instead of the Fe₅₆Pt₄₄ thin film as the hard magneticthin film, and therefore, only the structure of the movable mirrorportion is illustrated. FIGS. 12A and 12B are schematic diagramsillustrating the movable mirror portion of the two-dimensional opticalscanning mirror device according to Example 2 of the present invention.FIG. 12A is an upper diagram, and FIG. 12B is a cross-sectional diagramalong the single-dotted chain line connecting A and A″ in FIG. 12A.Though the size of the reflection portion 80 and the entire size of themovable mirror portion 70 are arbitrary, the size of the reflectionportion 80 is 500 μm×300 μm, and the size of the movable mirror portionis 2.7 mm×2.5 mm. A Si substrate 71 is used to provide a Co₈₀Pt₂₀ thinfilm 77 having a thickness of 160 nm with a SiO₂ film 72 in between. Areflection portion 80, hinges 81, a rotational outer frame 82, hinges 83and a non-rotational outer frame 44 are formed of a metal glass film 75.Here, a Si layer is provided as a mirror base substrate 76 on theopposite side of the SiO₂ film contacting the Co₈₀Pt₂₀ thin film 77.

Annealing treatment was carried out in a vacuum at a temperature of 670°C. for 15 minutes on the Co₈₀Pt₂₀ thin film 77 after the formation ofthe film. The coercive force of the Co₈₀Pt₂₀ thin film 77 in the planedirection was approximately 200 kA/m. In addition, the residualmagnetization was approximately 0.6 tesla. Furthermore, the Co₈₀Pt₂₀thin film 77 was magnetized with the intensity of the magnetic field of5 tesla, and the time for magnetization was three minutes.

In the same manner as in FIG. 8, a solenoid coil having the samestructure was installed in the two-dimensional optical scanning mirrordevice in Example 2. As for the size of the coil, the outer diameter was5 mm, the height was 3 mm and the number of turns of the wire was 800.This two-dimensional optical scanning mirror device was irradiated witha laser beam so that the reflected light was projected onto a screen,and the deflection angle of the light beam was evaluated, and then, thesame effects as in Example 1 were gained. In addition, thecharacteristics were measured after a bar magnet for science education(the magnitude of the magnetic field was approximately 50 kA/m) was madeto approach the two-dimensional optical scanning mirror device as anexternal magnetic field, and then, a slight deterioration of thecharacteristics was observed. Concerning the operational characteristicsafter the two-dimensional optical scanning mirror device had been inoperation for one month, though a deterioration of the operationalcharacteristics was perceived, it was in a range that does not affectpractical use. It can be seen from these results that thetwo-dimensional optical scanning mirror device is not affected by achange in the general external environment such as the temperature or anexternal magnetic field or the repetitive use of the mirror as long asthe coercive force of the magnetic thin film is 100 kA/m or greater.

Example 3

Next, the two-dimensional optical scanning mirror device according toExample 3 of the present invention is described in reference to FIGS.13A and 13B and is the same as that in Example 1, except that a Co₈₀Pd₂₀thin film is used instead of the Fe₅₆Pt₄₄ thin film as the hard magneticthin film, and therefore, only the structure of the movable mirrorportion is illustrated. FIGS. 13A and 13B are schematic diagramsillustrating the movable mirror portion of the two-dimensional opticalscanning mirror device according to Example 3 of the present invention.FIG. 13A is an upper diagram, and FIG. 13B is a cross-sectional diagramalong the single-dotted chain line connecting A and A″ in FIG. 13A.Though the size of the reflection portion 80 and the entire size of themovable mirror portion 70 are arbitrary, the size of the reflectionportion 80 is 500 μm×300 μm, and the size of the movable mirror portionis 2.7 mm×2.5 mm. A Si substrate 71 is used to provide a Co₈₀Pd₂₀ thinfilm 78 having a thickness of 150 nm with a SiO₂ film 72 in between. Areflection portion 80, hinges 81, a rotational outer frame 82, hinges 83and a non-rotational outer frame 44 are formed of a metal glass film 75.Here, a Si layer is provided as a mirror base substrate 76 on theopposite side of the SiO₂ film contacting the Co₈₀Pd₂₀ thin film 78.

Annealing treatment was carried out in a vacuum at a temperature of 650°C. for 15 minutes on the Co₈₀Pd₂₀ thin film 78 after the formation ofthe film. The coercive force of the Co₈₀Pd₂₀ thin film 78 in the planedirection was approximately 160 kA/m. In addition, the residualmagnetization was approximately 0.5 tesla. Furthermore, the Co₈₀Pd₂₀thin film 78 was magnetized with the intensity of the magnetic field of5 tesla, and the time for magnetization was three minutes.

In the same manner as in FIG. 8, a solenoid coil having the samestructure was installed in the two-dimensional optical scanning mirrordevice in Example 3. As for the size of the coil, the outer diameter was5 mm, the height was 3 mm and the number of turns of the wire was 800.This two-dimensional optical scanning mirror device was irradiated witha laser beam so that the reflected light was projected onto a screen,and the deflection angle of the light beam was evaluated, and then, thesame effects as in Example 1 were gained. In addition, thecharacteristics were measured after a bar magnet for science education(the magnitude of the magnetic field was approximately 50 kA/m) was madeto approach the two-dimensional optical scanning mirror device as anexternal magnetic field, and then, a slight deterioration of thecharacteristics was observed. Concerning the operational characteristicsafter the two-dimensional optical scanning mirror device had been inoperation for one month, though a deterioration of the operationalcharacteristics was perceived, it was in a range that does not affectpractical use. It can be seen from these results that thetwo-dimensional optical scanning mirror device is not affected by achange in the general external environment such as the temperature or anexternal magnetic field or the repetitive use of the mirror as long asthe coercive force of the magnetic thin film is 100 kA/m or greater.

Example 4

Next, the two-dimensional optical scanning mirror device according toExample 4 of the present invention is described in reference to FIGS.14A and 14B and is the same as that in Example 1, except that anFe₅₆Pt₄₄ thin film having a two-layer structure is used instead of theFe₅₆Pt₄₄ thin film having a single layer structure as the hard magneticthin film, and therefore, only the structure of the movable mirrorportion is illustrated. FIGS. 14A and 14B are schematic diagramsillustrating the movable mirror portion of the two-dimensional opticalscanning mirror device according to Example 4 of the present invention.FIG. 14A is an upper diagram, and FIG. 14B is a cross-sectional diagramalong the single-dotted chain line connecting A and A″ in FIG. 14A.Though the size of the reflection portion 80 and the entire size of themovable mirror portion 70 are arbitrary, the size of the reflectionportion 80 is 500 μm×300 μm, and the size of the movable mirror portionis 2.7 mm×2.5 mm.

A Si substrate 71 is used to provide an Fe₅₆Pt₄₄ thin film 74 ₁ having athickness of 140 nm, a SiO₂ film 79 having a thickness of 70 nm, and anFe₅₆Pt₄₄ thin film 742 having a thickness of 140 nm with a SiO₂ film 72in between. A reflection portion 80, hinges 81, a rotational outer frame82, hinges 83 and a non-rotational outer frame 44 are formed of a metalglass film 75. Here, a Si layer is provided as a mirror base substrate76 on the opposite side of the SiO₂ film 72 contacting the Fe₅₆Pt₄₄ thinfilm 741.

In this case, the coercive force in the plane direction and the residualmagnetization were approximately the same as in the case of Example 1,and the characteristics that are better as compared to Example 1 weregained in terms of the deflection angle of the beam. Here, the magneticfield generated outside becomes greater when the hard magnetic thin filmis made to have a two-layer structure as in Example 4.

Example 5

Next, the two-dimensional optical scanning mirror device according toExample 5 of the present invention is described in reference to FIGS.15A and 15B and is the same as that in Example 1, except that anFe₅₆Pt₄₄ thin film having a multilayer structure is used instead of theFe₅₆Pt₄₄ thin film having a single layer structure as the hard magneticthin film, and therefore, only the structure of the movable mirrorportion is illustrated. FIGS. 15A and 15B are schematic diagramsillustrating the movable mirror portion of the two-dimensional opticalscanning mirror device according to Example 5 of the present invention.FIG. 15A is an upper diagram, and FIG. 15B is a cross-sectional diagramalong the single-dotted chain line connecting A and A″ in FIG. 15A.Though the size of the reflection portion 80 and the entire size of themovable mirror portion 70 are arbitrary, the size of the reflectionportion 80 is 500 μm×300 μm, and the size of the movable mirror portionis 2.7 mm×2.5 mm.

An Fe₅₆Pt₄₄ thin film 74 ₃ having a thickness of 120 nm, a SiO₂ film 79₁ having a thickness of 70 nm, an Fe₅₆Pt₄₄ thin film 74 ₄ having athickness of 120 nm, a SiO₂ film 792 having a thickness of 5 nm, and anFe₅₆Pt₄₄ thin film 74 ₅ having a thickness of 120 nm were sequentiallyformed on a Si substrate 71 with a SiO₂ film 72 in between. A reflectionportion 80, hinges 81, a rotational outer frame 82, hinges 83 and anon-rotational outer frame 44 are formed of a metal glass film 75. Here,a Si layer is provided as a mirror base substrate 76 on the oppositeside of the SiO₂ film 72 contacting the Fe₅₆Pt₄₄ thin film 741.

In this case, the coercive force in the plane direction and the residualmagnetization were approximately the same as in the case of Example 1,and the characteristics that are better as compared to Example 1 weregained in terms of the deflection angle of the beam. Furthermore, thesame characteristics were gained in the case where the hard magneticthin film has a four-layer structure with SiO₂ films in between. Amagnetic field generated outside becomes greater when the hard magneticthin film has a multilayer structure as in Example 5.

Example 6

Next, the two-dimensional optical scanning mirror device according toExample 6 of the present invention is described in reference to FIGS.16A and 16B and is the same as that in Example 1, except the thicknessof the Fe₅₆Pt₄₄ thin film, and therefore, only the structure of themovable mirror portion is illustrated. FIGS. 16A and 16B are schematicdiagrams illustrating the movable mirror portion of the two-dimensionaloptical scanning mirror device according to Example 6 of the presentinvention. FIG. 16A is an upper diagram, and FIG. 16B is across-sectional diagram along the single-dotted chain line connecting Aand A″ in FIG. 16A. Though the size of the reflection portion 80 and theentire size of the movable mirror portion 70 are arbitrary, the size ofthe reflection portion 80 is 500 μm×300 μm, and the size of the movablemirror portion is 2.7 mm×2.5 mm.

Here, the thickness of the Fe₅₆Pt₄₄ thin film 74 was 88 nm, 210 nm, 460nm or 580 nm. The thicker the thin film is, the lower the drive voltageis for obtaining the same deflection angle of the beam as in Example 1.However, the basic characteristics are the same as in Example 1.

Example 7

Next, the two-dimensional optical scanning mirror device according toExample 7 of the present invention is described in reference to FIGS.17A through 17I, which is the same as that in Example 1 except for themanufacturing process procedures, and therefore, only the manufacturingprocess is described. First, as illustrated in FIG. 17A, a siliconsubstrate 71 having a thickness of 0.4 mm and of which the main surfaceis (100) plane is heated at 1000° C. for one hour in the air so that theSiO₂ films 72 and 73 having a thickness of 10 nm to 100 nm are formed.Here, the thickness of the SiO₂ film 72 is 100 nm.

Next, as illustrated in FIG. 17B, an Fe₅₆Pt₄₄ thin film 74 having athickness of 142 nm is deposited in accordance with an electron beamheating vapor deposition method. After that, the substrate is irradiatedwith infrared rays in a vacuum so as to be annealed, and thus, theFe₅₆Pt₄₄ thin film 74 is converted to an alloy. Here, the temperaturefor heating is 650° C., and the time for heating is 15 minutes. Then,the Fe₅₆Pt₄₄ thin film 74 is magnetized by applying a magnetic field tothe Si substrate 71 in the <011> direction. Here, the intensity of themagnetic field for magnetization is 5 tesla, and the time formagnetization is three minutes.

Next, as illustrated in FIG. 17C, the Fe₅₆Pt₄₄ thin film 74 is processedin accordance with an ion milling method to shapes that correspond tothe rotational outer frame 82 and the reflection portion 80 asillustrated in FIG. 8. At this time, the direction of the hinges 81 and83, that is to say, the optical scanning rotation axis of the mirrorportion, becomes the same as the <010> direction of the Si substrate 71,and thus, the magnetization direction is at 45° relative to the hinges81 and 83. Then, as illustrated in FIG. 17D, a buffered HF solution isused to etch the SiO₂ film 73 to a pattern that corresponds to thepatterned Fe₅₆Pt₄₄ thin film 74 and the outer peripheral portion of theSi substrate 71.

Next, as illustrated in FIG. 17E, a metal glass film 75 of which thepattern corresponds to the reflection portion 80, the hinge 81, therotational outer frame 82, the hinge 83 and the non-rotational outerframe 84 is formed in accordance with a lift-off method. A film ofZr₇₅Cu₃₀Al₁₀Ni₅ having a thickness of 10 μm is formed as the metal glassfilm 75 in accordance with a sputtering method in an atmosphere of whichthe pressure has been reduced to 0.4 Pa.

Next, as illustrated in FIG. 17F, the Si substrate 71 is etched on thebottom side using the SiO₂ film 73 as a mask until the SiO₂ film 72 ispartially exposed. Then, as illustrated in FIG. 17G, a buffered HFsolution is used to remove the SiO₂ film 73 except the portion that ismade to remain around the periphery.

Next, as illustrated in FIG. 17H, the SiO₂ film 73 that remains aroundthe periphery is used as a mask so as to etch the Si substrate 71 insuch a manner that a Si layer having a thickness of 100 μm remains as amirror base substrate 76. Then, as illustrated in FIG. 17I, a bufferedHF solution is used to completely etch the exposed portion of the SiO₂film 72 so that the hinges 81 and 83 consist of only the metal glassfilm 75. Then, the Si substrate 71 is diced to cut out a two-dimensionaloptical scanning mirror device, and thus, the basic structure of themovable mirror portion 70 of the two-dimensional scanning mirror deviceaccording to Example 7 of the present invention is complete.

Thought the manufacturing process is different, the final structure inExample 7 is the same as in Example 1, and therefore, the samecharacteristics as in Example 1 are gained.

Example 8

Next, the two-dimensional optical scanning mirror device according toExample 8 of the present invention is described in reference to FIGS.18A and 18B and is the same as in Example 1 except that the Fe₅₆Pt₄₄thin film 74 is used as a reflective film and does not form the SiO₂film 72 having a thickness of approximately 100 nm that is formed inExample 1, and therefore, only the structure of the movable mirrorportion is illustrated. FIGS. 18A and 18B are schematic diagramsillustrating the movable mirror portion of the two-dimensional opticalscanning mirror device according to Example 8 of the present invention.FIG. 18A is an upper diagram, and FIG. 18B is a cross-sectional diagramalong the single-dotted chain line connecting A and A″ in FIG. 18A.Though the size of the reflection portion 80 and the entire size of themovable mirror portion 70 are arbitrary, here, the size of thereflection portion 80 is 500 μm×300 μm, and the size of the movablemirror portion 70 is 2.7 mm×2.5 mm.

As illustrated in FIGS. 18A and 18B, an Fe₅₆Pt₄₄ thin film 74 isprovided on a Si substrate 71 with an extremely thin SiO₂ film (notshown) in-between, and the Si substrate 71 is etched on the bottom sidein such a manner that the portion of a Si layer having a thickness of100 μm that corresponds to the pattern of the Fe₅₆Pt₄₄ thin film 74 andthe portions of the Si layer that correspond to the hinge 81, therotational outer frame 82, the hinge 83 and the non-rotational outerframe 84 remain as the mirror base substrate 76. In this case as well,approximately the same characteristics as in Example 1 are gained.

Example 9

Next, the two-dimensional optical scanning mirror device according toExample 9 of the present invention is described in reference to FIGS.19A and 19B as is basically the same as in Example 1 except that theFe₅₆Pt₄₄ thin film 74 is used as a reflective film, and therefore, onlythe structure of the movable mirror portion is illustrated. FIGS. 19Aand 19B are schematic diagrams illustrating the movable mirror portionof the two-dimensional optical scanning mirror device according toExample 9 of the present invention. FIG. 19A is an upper diagram, andFIG. 19B is a cross-sectional diagram along the single-dotted chain lineconnecting A and A″ in FIG. 19A. Though the size of the reflectionportion 80 and the entire size of the movable mirror portion 70 arearbitrary, here, the size of the reflection portion 80 is 500 ∞m×300 μm,and the size of the movable mirror portion 70 is 2.7 mm×2.5 mm.

As illustrated in FIGS. 19A and 19B, an Fe₅₆Pt₄₄ thin film 74 isprovided on a Si substrate 71 with a SiO₂ film 72 in between, and the Sisubstrate 71 is etched on the bottom side in such a manner that the Sisubstrate 71 remains only around the periphery of the non-rotationalouter frame 84. Then, the SiO₂ film 72 in the region between thereflection portion 80 and the rotational outer frame 82 is removedthrough etching, except the portions that correspond to the hinges 81.In this case as well, approximately the same characteristics as inExample 1 are gained.

Example 10

Next, the two-dimensional optical scanning device according to Example10 of the present invention is described in reference to FIG. 20. FIG.20 is a schematic perspective diagram illustrating the two-dimensionaloptical scanning device according to Example 10 of the presentinvention. A two-dimensional optical scanning mirror device having thesame structure as in Example 1 is used as a two-dimensional opticalscanning mirror portion.

First, a SiO₂ film 102 having a thickness of 15 μm is formed on a Sisubstrate 101 having a thickness of 500 μm in accordance with a flamehydrolysis method. Then, a film of a SiO₂—GeO₂ layer having a thicknessof 2 μm (refraction index difference Δn=0.5%, where Δn is defined asΔn=(n₁−n₂)/n₁, n₁ is the refraction index of the core, and n₂ is therefraction index of the clad) is formed on the SiO₂ film 102 inaccordance with a flame hydrolysis method. On top of this, patternedoptical waveguides 104 through 106 having a width of 2 μm are formed asan optical multiplexer 103 in accordance with a light exposure methodusing a contact mask.

Next, a SiO₂ film having a thickness of 20 μm (not shown) is formed inaccordance with a flame hydrolysis method as an upper clad layer, whichcovers the entire pattern of the optical waveguides 104 through 106.Here, it is necessary to bend the light incident portion of thepatterned optical waveguide 104 for red and the patterned opticalwaveguide 106 for blue at a right angle, and therefore, a deep trenchhaving a depth of 30 μm is created in the portions to be bent throughetching in accordance with a conversion ion beam method using Ga so thatthe guided light makes total reflection from the sidewalls of thetrenches. Then, the SiO₂ film is completely removed through etchingexcept for only in the optical multiplexer 103 region so as to leave theSi substrate 101 in an exposed state.

Next, concerning Example 1, a two-dimensional optical scanning mirrorportion 108 is formed in the process illustrated in FIGS. 10A through10I. Here, the entirety of this manufacturing process is basicallycarried out at a temperature of 200° C. or lower after magnetization sothat the characteristics of the Fe₅₆Pt₄₄ thin film as a permanent magnetdo not disappear. Here, 107 in the diagrams denotes a SiO₂ film.

Next, a red semiconductor laser chip 109, a green semiconductor laserchip 110 and a blue semiconductor laser chip 111 are bonded on the Sisubstrate 101 so that light can enter into the patterned opticalwaveguides 104 through 106. At this time, the Si substrate 101 is etchedto a predetermined depth so that the laser emitting ends of the redsemiconductor laser chip 109, the green semiconductor laser chip 110 andthe blue semiconductor laser chip 111 match the positions of thepatterned optical waveguides 104 through 106, respectively.

Next, a solenoid coil 112 for driving the reflection portion of thetwo-dimensional optical scanning mirror device 108 is arranged on thelower side of the Si substrate 101 so as to be fixed to the Si substrate101 using an adhesive. At this time, the mirror surface of thereflection portion is inclined by 45° relative to the light beam that isapproximately parallel to the main surface of the substrate 101 in astate where an optical scanning signal is not applied to the solenoidcoil 112. That is to say, the reflection portion is placed so as to beinclined by 45° relative to the light beam by means of a mechanicalexternal force, and the hinges made of metal glass are irradiated with afocused laser beam (beam diameter: 70 μm, output: 10 mW) so as tolocally heat the hinges, and thus, the reflection portion is fixed in aninclined state of 45°. As a result, the stress caused on the hinges canbe mitigated, and thus, the reflection portion stays inclined by 45°even when the external force is removed. At this time, the mechanicalexternal force is applied by using a probe (cantilever). As for the sizeof this two-dimensional optical scanning device, the length is 6 mm, thewidth is 3 mm and the height is 3 mm, and thus, ultra-miniaturizationcan be achieved.

In order to make the mirror surface incline by 45° relative to the lightbeam from the beginning in a state where an optical scanning signal isnot applied to the solenoid coil 112, a constant direct current may bemade to flow through the solenoid coil 112. When an alternating signalis made to flow in addition to this direct current, the scanning mirrorcan be rotated with the position that is inclined by 45° being thecenter.

Alternatively, a permanent magnet can be arranged in the vicinity of thesolenoid coil 112 so that the mirror surface inclines by 45° relative tothe light beam. In this case, the scanning mirror can be rotated withthe position that is inclined by 45° being the center by simply allowingan alternating signal to flow through the solenoid coil 112.

In Example 10, an optical multiplexer and a movable mirror portion areintegrated on a Si substrate, and therefore, the total size of thetwo-dimensional optical scanning device can be made compact, which ispreferable as the two-dimensional optical scanning device for aspectacle-type retina scanning display.

Example 11

Next, the two-dimensional optical scanning device according to Example11 of the present invention is described in reference to FIG. 21 and isthe same as in Example 10 except for the position of the solenoid coil,and therefore, only the portion in the vicinity of the solenoid coil isillustrated. FIG. 21 is a side diagram illustrating the portion in thevicinity of the solenoid coil of the two-dimensional optical scanningdevice according to Example 11 of the present invention. The center axisof the solenoid coil 112 having an outer diameter of 5 mm and a heightof 3 mm and of which the number of turns of the wire is 800 is arrangedin a place that is shifted by 1 mm from the center portion of thetwo-dimensional scanning mirror portion 108 in the direction of thelaser beam.

When the center axis of the solenoid coil 112 is shifted by 1 mm fromthe center portion of the two-dimensional scanning mirror portion 108 inthe direction of the laser beam as described above, the end portion ofthe magnetized two-dimensional scanning mirror portion 108 and thesolenoid coil 112 are made to be in proximity to each other, and thus,the interaction becomes greater. Therefore, the intensity of the directcurrent can be reduced by 50% as compared to the case where the centeraxis of the solenoid coil 112 matches the center portion of thetwo-dimensional scanning mirror portion 108. In this case as well, analternating signal can be made to flow in addition to the direct currentso that the scanning mirror can be rotated with the position that isinclined by 45° being the center. Here, 113, 114 and 115 in FIG. 21denote an Fe₅₆Pt₄₄ thin film, a metal glass film and a mirror basesubstrate, respectively.

Example 12

Next, the two-dimensional optical scanning device according to Example12 of the present invention is described in reference to FIG. 22. FIG.22 is a schematic perspective diagram illustrating the two-dimensionaloptical scanning device according to Example 12 of the presentinvention. A two-dimensional optical scanning mirror device having thesame structure as in Example 1 is used as the two-dimensional opticalscanning mirror portion.

A two-dimensional optical scanning mirror device 130 having a solenoidcoil 133 is mounted on a mounting substrate 120, and at the same time, alight source device 140 is mounted in such a location that thetwo-dimensional optical scanning mirror device 130 is irradiated with alaser beam. This light source device has the same structure as the lightsource unit in the two-dimensional optical scanning device in Example10. That is to say, patterned optical waveguides 144 through 146 areprovided on a Si substrate 141 with a SiO₂ film 142 in between, and aSiO₂ film (not shown) that becomes an upper clad layer is provided ontop of that so as to form an optical multiplexer 143. Then, the SiO₂film 142 in the region other than the region where the opticalmultiplexer 143 has been formed is removed so as to expose the Sisubstrate 141. Here, 131 and 132 in FIG. 22 denote a Si substrate and aSiO₂ film, respectively.

Next, a red semiconductor laser chip 147, a green semiconductor laserchip 148 and a blue semiconductor laser chip 149 are bonded on the Sisubstrate 141 so that light can enter into the patterned opticalwaveguides 144 through 146. At this time, the Si substrate 141 is etchedto a predetermined depth so that the laser emitting ends of the redsemiconductor laser chip 147, the green semiconductor laser chip 148 andthe blue semiconductor laser chip 149 match the positions of thepatterned optical waveguides 144 through 146, respectively.

In Example 12 of the present invention, the two-dimensional opticalscanning mirror device 130 and the light source device 140 are formed ondifferent substrates, and therefore, the respective manufacturingprocesses have fewer limitations in terms of the temperature for heattreatment or the etching conditions. Here, the mounting substrate may bean insulating substrate such as a sapphire substrate, a metal substrateor a printed circuit board, taking the electrical connections to thetwo-dimensional optical scanning mirror device 130 and the light sourcedevice 140 into consideration.

Here, the following supplementary notes are added concerning theembodiments of the present invention including Examples 1 through 12.

-   (1) A two-dimensional optical scanning mirror device, comprising: a    substrate; a movable mirror portion supported on the substrate in    such a manner that two-dimension optical scanning is possible; a    hard magnetic thin film provided in the movable mirror portion; and    a magnetic field generator that includes at least an alternating    magnetic field generator for driving the movable mirror portion,    wherein the hard magnetic thin film has a magnetization direction in    a direction of a film plane, and the ratio of the magnetic field    generated by the magnetic field generator relative to the coercive    force of the hard magnetic thin film is 0.2 or lower.-   (2) The two-dimensional optical scanning mirror device according to    (1), wherein the hard magnetic thin film becomes a reflecting    mirror.-   (3) The two-dimensional optical scanning mirror device according to    (1), further comprising a reflective film that becomes a reflecting    mirror at least on a surface of the hard magnetic thin film.-   (4) The two-dimensional optical scanning mirror device according to    any of (1) through (3), wherein the movable mirror portion    comprises: a reflection portion; a rotational outer frame for    supporting the reflection portion with a pair of first hinges; and a    non-rotational outer frame for supporting the rotational outer frame    with a pair of second hinges provided in the direction that is    orthogonal to the first hinges.-   (5) The two-dimensional optical scanning mirror device according to    (4), wherein the rotational outer frame and the non-rotational outer    frame are formed of metal glass that also functions as a reflecting    mirror.-   (6) The two-dimensional optical scanning mirror device according to    (4), wherein the rotational outer frame and the non-rotational outer    frame are formed of a non-magnetic dielectric film and the hard    magnetic thin film is provided on the reflection portion and the    rotational outer frame.-   (7) The two-dimensional optical scanning mirror device according to    any of (1) through (6), wherein the coercive force of the hard    magnetic thin film is 100 kA/m or greater.-   (8) The two-dimensional optical scanning mirror device according to    any of (1) through (7), wherein the hard magnetic thin film is made    of a magnetic material of which the main components are Fe and Pt, a    magnetic material of which the main components are Co and Pt, or a    magnetic material of which the main components are Fe and Pd.-   (9) The two-dimensional optical scanning mirror device according to    any of (1) through (8), wherein the magnetization direction of the    hard magnetic thin film is at an angle within a range of 45°+/−30°    relative to the optical scanning rotation axis of the movable mirror    portion.-   (10) The two-dimensional optical scanning mirror device according to    any of (1) through (9), wherein the reflective surface of the    movable mirror portion inclines by an angle within a range of    45°+/−30° relative to the main surface of the substrate in a state    where an optical scanning signal is not applied to the alternating    magnetic field generator.-   (11) The two-dimensional optical scanning mirror device according to    any of (1) through (9), wherein the substrate is a single crystal Si    substrate.-   (12) A manufacturing method for a two-dimensional optical scanning    mirror device, comprising: forming a hard magnetic thin film on a    substrate; magnetizing the hard magnetic thin film; and forming a    movable mirror portion by processing the magnetized hard magnetic    thin film.-   (13) The manufacturing method for a two-dimensional optical scanning    mirror device according to (12), further comprising annealing the    hard magnetic thin film before the step of magnetizing the hard    magnetic thin film.-   (14) A two-dimensional optical scanning device, comprising: the    two-dimensional optical scanning mirror device according to any    of (1) through (13); and a light source formed on the substrate.-   (15) A two-dimensional optical scanning device, comprising: the    two-dimensional optical scanning mirror device according to any    of (1) through (13); a mounting substrate on which the    two-dimensional optical scanning mirror device is mounted; and a    light source that is mounted in such a location that the    two-dimensional optical scanning mirror device on the mounting    substrate is irradiated with a laser beam.-   (16) The two-dimensional optical scanning device according to (14)    or (15), wherein the light source comprises a red laser, a green    laser, a blue laser and an optical multiplexer for multiplexing the    light outputted from the red laser, the green laser and the blue    laser.-   (17) An image projector, comprising: the two-dimensional optical    scanning device according to any of (14) through (16); a    two-dimensional optical scanning controller for two-dimensionally    scanning the emission light emitted from the light source by    applying a two-dimensional optical scanning signal to the    alternating magnetic field generator; and an image formation unit    for projecting the scanned emission light onto a projection surface.

REFERENCE SIGNS LIST

10 movable mirror unit

11 first hinge

12 rotational outer frame

13 second hinge

14 non-rotational outer frame

20 reflection portion

21 substrate

22 hard magnetic thin film

23 reflective film

30 magnetic field generator

31 alternating magnetic field generator

32 permanent magnet

41 optical multiplexer

42 red laser

43 green laser

44 blue laser

50 control unit

51 controller

52 operating unit

53 external I/F

54 R laser driver

55 G laser driver

56 B laser driver

57 two-dimensional scanning driver

58 concave reflecting mirror

59 pupil

60 retina

70 movable mirror portion

71 Si substrate

72, 73 SiO₂ film

74, 74 ₁, 742, 74 ₃, 74 ₄, 74 ₅ Fe₅₆Pt₄₄ thin film

75 metal glass film

76 mirror base substrate

77 Co₈₀Pt₂₀ thin film

78 Co₈₀Pd₂₀ thin film

79, 79 ₁, 79 ₂ SiO₂ film

80 reflection portion

81, 83 hinge

82 rotational outer frame

84 non-rotational outer frame

90 solenoid coil

101 Si substrate

102 SiO₂ film

103 optical multiplexer

104-106 patterned optical waveguide

107 SiO₂ film

108 two-dimensional optical scanning mirror portion

109 red semiconductor laser chip

110 green semiconductor laser chip

111 blue semiconductor laser chip

112 solenoid coil

113 Fe₅₆Pt₄₄ thin film

114 metal glass film

115 mirror base substrate

120 mounting substrate

130 two-dimensional optical scanning mirror device

131 Si substrate

132 SiO₂ film

133 solenoid coil

140 light source device

141 Si substrate

142 SiO₂ substrate

143 optical multiplexer

144-146 patterned optical waveguide

147 red semiconductor laser chip

148 green semiconductor laser chip

149 blue semiconductor laser chip

The invention claimed is:
 1. A two-dimensional optical scanning mirrordevice, comprising: a substrate; a movable mirror portion supported on amain surface of the substrate in such a manner that two-dimensionoptical scanning is possible, wherein the movable mirror portionincludes, a reflection portion which reflects a light beam beingincident along the main surface of the substrate, a rotational outerframe which supports the reflection portion with a pair of first hinges,and a non-rotational outer frame, mounted on the main surface of thesubstrate, which supports the rotational outer frame with a pair ofsecond hinges, the pair of first hinges provides a high-speed opticalscanning rotation axis for rotating the reflection portion so as to scana reflection light beam reflected by the reflection portion in a firstdirection with a first frequency, the pair of second hinges, providedorthogonal to the pair of first hinges, provides a low-speed opticalscanning rotation axis for rotating the rotational outer frame so as toscan the reflection light beam in a second direction orthogonal to thefirst direction with a second frequency lower than the first frequency,a rotation of the pair of first hinges has an inherent rotationfrequency approximate to the first frequency, a reflective surface ofthe reflection portion of the movable mirror portion inclines by anangle within a range of 45°+/−30° relative to the main surface of thesubstrate in a state where an optical scanning signal fortwo-dimensionally scanning the movable mirror portion is not applied. 2.The two-dimensional optical scanning mirror device according to claim 1,further comprising: a hard magnetic thin film provided on the reflectionportion of the movable mirror portion; and a magnetic field generatorthat includes at least an alternating magnetic field generator fordriving the reflection portion and the rotational outer frame of themovable mirror portion, wherein the hard magnetic thin film has amagnetization direction in a direction of a film plane, and the ratio ofthe magnetic field generated by the magnetic field generator relative tothe coercive force of the hard magnetic thin film is 0.2 or lower. 3.The two-dimensional optical scanning mirror device according to claim 2,wherein the hard magnetic thin film becomes a reflecting mirror of thereflection portion.
 4. The two-dimensional optical scanning mirrordevice according to claim 2, further comprising a reflective film thatbecomes a reflecting mirror of the reflection portion at least on asurface of the hard magnetic thin film.
 5. The two-dimensional opticalscanning mirror device according to claim 2, wherein the coercive forceof the hard magnetic thin film is 100 kA/m or greater.
 6. Thetwo-dimensional optical scanning mirror device according to claim 2,wherein the magnetization direction of the hard magnetic thin film is atan angle within a range of 45°+/−30° relative to the high-speed opticalscanning rotation axis and the low-speed optical scanning rotation axisof the movable mirror portion.
 7. A two-dimensional optical scanningdevice, comprising: the two-dimensional optical scanning mirror deviceaccording to claim 1; and a light source formed on the substrate.
 8. Atwo-dimensional optical scanning device, comprising: the two-dimensionaloptical scanning mirror device according to claim 1; a mountingsubstrate on which the two-dimensional optical scanning mirror device ismounted; and a light source that is mounted in such a location that thetwo-dimensional optical scanning mirror device on the mounting substrateis irradiated with the light beam.
 9. An image projector, comprising:the two-dimensional optical scanning device according to claim 7; atwo-dimensional optical scanning controller for two-dimensionallyscanning the emission light emitted from the light source by applying atwo-dimensional optical scanning signal; and an image formation unit forprojecting the scanned emission light onto a projection surface.
 10. Animage projector, comprising: the two-dimensional optical scanning deviceaccording to claim 8; a two-dimensional optical scanning controller fortwo-dimensionally scanning the emission light emitted from the lightsource by applying the optical scanning signal; and an image formationunit for projecting the scanned emission light onto a projectionsurface.